A converter bridge is known, for example, from the European patent publication EP-B1 0 254 911.
The converter bridge in this publication is a so-called two point converter, which is constructed in essence from two half bridges or converter switching poles. Each half bridge comprises two switchable thyristors (e.g. GTOs), which are connected in series and to which a free-wheeling diode is inversely parallelly connected. A supporting capacitor is connected parallel to each converter switching pole. The converter switching poles are connected to a converter bridge by means of connecting bars or bus bars.
A direct current source is connected to these bus bars. The GTOs are switched on and off only so that alternating current flows through the load. In addition, a high frequency, parasitic oscillating current is created, through the switching operation of the GTOs, in the oscillating circuit, formed by means of the supporting capacitors and the inductances of the bus bars. In addition to the operating current, this high frequency oscillating current also loads the bus bars and the supporting capacitors. Thus, it represents an undesired disturbing component, such that, on the one hand, the losses rise and, on the other hand, the converter is unnecessarily loaded.